BRUSSELS, Belgium — A major natural gas pipeline exploded Friday in Belgium, killing as many as 15 people and injuring more than 100, including firefighters and police responding to a report of a leak, officials said.

The explosion in the industrial area of Ghislenghien, 20 miles southeast of Brussels, the capital, happened after construction workers pierced an underground gas distribution line, acting provincial Gov. Guy Petit said.

The early morning blast was seen and felt several miles away, shaking the ground like an earthquake. Giant orange flames soared into the sky and charred nearby cars and wheat fields.

Two nearby factories also caught fire, Belgian media reported. The Electrabel company denied reports that one of its buildings was gutted but said one of its employees was killed.

There were conflicting reports on the number of dead and injured. Defense Minister Andre Flahaut, on a visit to the scene of the blast, said 15 people were known to have died, while Health Ministry spokeswoman Michele Vanderplaetsen said only 10 deaths had been confirmed. Flahaut said 112 were injured, and Belgian media put the number at nearly 200.

The injured were sent to six specialized burn units across Belgium and northern France.

“There are many serious burn victims, with serious burns mostly on their backs ... There are some 20 or so that are fighting for their lives,” said Dr. Jean Francois Breckx at a military hospital in Neder-Over-Heembeek, a suburb of Brussels.

Firefighters sprayed water trying to cool the broken pipeline in a large crater gouged by the blast.

“I had the impression that a plane was going to crash on the house,” Carine Vanus in Ath, 6 miles away, told RTL television. “When we got out on the street we saw a billow of white smoke and the sound was deafening.”

Elise Hoffmann, who lives 2½ miles away in Silly, told RTL her house trembled and she ran outside to see flames shooting more than 100 yards into the air. “It happened 45 minutes ago and I still shiver,” she said.

People were advised to stay indoors and shut their windows and doors to keep out smoke that hung over the area, but the Health Ministry said it was not toxic and no evacuation was ordered. The E429 motorway, which links Brussels and Lille, France, was closed.

Army units were called in to help coordinate the disaster response, involving dozens of ambulances and six military helicopters to ferry victims to hospitals, including a Belgian military hospital burn unit.

France sent about 100 medical specialists to help treat victims and evacuate injured, French Health Minister Philippe Douste-Blazy said in a statement. Four helicopters and more than 20 units for treating the injured also were sent, French officials said.

Gas distributor Fluxys said the line that exploded runs from the Belgian port of Zeebrugge to France. It said a leak was reported about 30 minutes before the explosion.

Firefighters and police were investigating the leak when the blast occurred, and they were among the injured, according to the Interior Ministry.